InsectMotion - A Python-based tool for quantification of neuropeptide-induced organ contractions in arthropods

InsectMotion is a Python-based tool for analyzing video recordings of movements or muscle contractions in arthropods. It provides a simple, fast, and automated approach for semi-quantitative motion assessment by measuring "pixel activity", defined as changes in pixel intensity or colour. Unlike many existing methods, it does not require specialized equipment, chemical reagents, or expensive software. The application distinguishes active and inactive pixels within selected regions of interest (ROI) and quantifies their changes over a defined time period. InsectMotion offers two analysis modes: Graphical Analysis and Pixel Activity Analysis, both adaptable to various experimental setups. Graphical Analysis generates time-resolved plots of pixel activity, numerical outputs, and peak analysis. Pixel Activity Analysis produces binary images highlighting active pixel clusters and summary metrics describing active areas. Using immunohistochemistry, we detected calcitonin-like diuretic hormone (Bom-CT-DH) and myoinhibitory peptides (Bom-MIPs) in the innervation of digestive and reproductive organs of Bombyx mori. In vitro assays combined with InsectMotion quantified neuropeptide-induced contractions in these tissues. The tool was also applied on Ixodes ricinus in preliminary movement analyses, indicating its potential applicability beyond lepidopteran models. Our data show that InsectMotion is a reliable and accessible tool for in vitro and in vivo studies in neurobiology and physiology.